Dice the onion into small pieces and mince the garlic cloves, setting them aside for later.
Place the chicken breasts at the bottom of your slow cooker, spreading them out evenly.
Pour in the can of diced fire-roasted tomatoes and the drained beans over the chicken.
Add the diced onion and sprinkle the minced garlic on top of everything.
Sprinkle the chili powder and ground cumin over the ingredients, ensuring an even distribution of spices.
Cover the slow cooker and set it to low for 6 to 8 hours, allowing the flavors to meld and the chicken to become tender.
Once cooking is complete, open the lid and check if the chicken is tender and easily shredded with two forks.
Remove the chicken breasts, shred them into bite-sized pieces, and return to the chili mixture.
Squeeze fresh lime juice over the chili and stir well to brighten the flavors.
Taste and adjust the seasoning if needed, adding more spices or lime juice as desired.
Let the chili rest for about 10 minutes to allow flavors to settle before serving hot, topped with your favorite garnishes.